Electrically operated valves for delivering fluid under pressure

ABSTRACT

An electrically operated valve comprises a distributor having a slide operative to selectively place a fluid actuated device in communication with a source of pressurised fluid, or with a fluid outlet. The slide is actuated by an electrodynamic motor in response to a control signal, whereby the fluid pressure in the device is dependent on the signal.

United States Paten 1191 Grosseau Apr. 30, 1974 ELECTRICALLY OPERATEDVALVES FOR DELIVERING FLUID UNDER PRESSURE [75] Inventor: AlbertGrosseau, Chaville, France [73] Assignee: S.A. Automobiles Citroen,Paris,

France [22] Filed: June 6, 1972 [211 App]. No.: 260,272

[30] Foreign Application Priority Data 9/1968 Kubilos l37/625.6l X

Primary ExaminerHenry T. Klinksiek Attorney, Agent, or Firm-Eyre, Mann &Lucas ABSTRACT An electrically operated valve comprises a distributorhaving a slide operative to selectively place a fluid actuated device incommunication with a source of pressurised fluid, or with a fluidoutlet. The slide is actuated by an electrodynamic motor in response toa control signal, whereby the fluid pressure in the device [56]References Cited is dependent on the signal.

UNITED STATES PATENTS 3,179,123 4/1965 Kowalslri et al. 1'37 495 5 -10Claims, 7 Drawing Figures 1 ELECTRICALLY OPERATED VALVES FOR DELIVERINGFLUID UNDER PRESSURE FIELD OF THE INVENTION The present inventionrelates to electrically operated valves.

SUMMARY OF THE INVENTION According to the present invention, there isprovided in an electrically operated valve for delivering a fluidpressure governed by a control signal, feed pipe means, means definingan outlet, a distributor, said distributor having slide meansselectively placing the feed pipe means in communication with a sourceof fluid under pressure or with the outlet, means subjecting the slidemeans to an axial force dependent on pressure within an associatedfluid-actuated device and an electrodynamicmotor, said motor having awinding through which flows a current governed by the control signal,the said winding constituting the moving part of the electrodynamicmotor and being connected to the slide means,

In one embodiment of the invention, the force acting on the winding andthe force dependent on the pressure in the associated device areopposite in direction so as to balance each other at least partially;the pressure in the associated device is then an increasing function ofthe control signal.

In another embodiment of the invention, the force acting on the windingand the force dependent on the pressure in the associated device act inthe same direction, the valve having means for applying to the slidemeans a forceopposite in direction to the foregoing two forces; thepressure in the associated device is in this case a decreasing functionof the control signal. This embodiment of the invention is particularlyuseful in preventing wheel lock on a motor vehicle, the electricallyoperated valve being interposed between the pressure source and a brakecylinder of a braked wheel, the control winding being energised by asignal having a mean intensity dependent on, for instance, the degree ofwheel slip.

Preferably, the valve has a chamber connected to the feed pipe, withinwhich chamber a transmission or thrust member connected to the slidemeans and smaller in section than the latter is mounted with freedom tomove.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will nowbe described, by way of example only, with reference to the accompanyingdiagrammatic drawings, in which:

FIG. 1 is a section of one embodiment of a valve in accordance with theinvention;

FIG. 2 is a section, to an enlarged scale, of a portion of a valve; and

FIGS. 3 to 7 are sections showing details of other embodiments of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS a pressure source, and anoutlet passage 10, connected to a vent, openinto the grooves 4 and 5,respectively. The pressure source consists of a hydraulic accumulator11, charged from a tank 12 by a pump 13, and maintaining a pressure Phigher than that which normally exists in a fluid actuated device 15. Anintermediate feed pipe passage 14 is connected to the device 15,represented diagrammatically by a ram. According to the position of theslide 3, the passage 14 is either closed by the intermediate bearingportion 7 or partially or fully in communication with either the groove4 or the groove 5. One end of the bore 2 opens into a chamber 16 of thesame section, and which is connected to the passage 14 by a passage 17.

When axial force (F) is applied to the end of the slide 3 remote fromthe chamber 16, the slide 3 moves to the right (as viewed in FIG. 1),placing the passage 14 in communication with the passage 9 and hencewith the high-pressure source. The pressure which then acts in thedevice 15 and hence in the chamber 16 acts as a fluid actuated devicethat tends to move the slide 3 towards the left. There is finallyestablished in the device 15 a pressure (P,,) proportional to F, itsvalue here being F/S, where S is the cross-sectional area of the endface of the bearing portion 8. Any variation in the force F or pressureP results in displacement of the slide 3 so as to alter the ratio of thepressure differentials between the passage 14 and the grooves 4 and 5,that is to say between the pressure source and the vent, in a directioncorresponding to the restoration of equilibrium.

The slide 3 is actuated by an electrodynamic motor; in other words themotor applies the force F to the slide 3. The motor incorporates apermanent magnet 18 mounted between a pole piece 19 and the end wall ofa pot-shaped magnetic yoke 20 so as to define, in conjunction with thepole piece 19, an annular gap 21; the yoke 20 is fixed to the body 1 ofthe distributor.

Mounted within the gap 21 is a winding 22 supported on a cup 23. The cup23 is biased against the end of the slide 3 by a spring 24; a spring 25mounted within the chamber 16, acts in opposition to the spring 24whereby, when a control signal is zero, the slide is located in anequilibrium position in which the axial surface of the bearing portion 7which faces towards the groove 5 lies in the transverse plane of thatposition of the generator line of the passage 14 which is nearest to thegroove 5 (as shown in FIG. 2).

In this way, in the absence of current in the winding 22, the pressurein the connection to the deivce 15 is zero; but when current is passedthrough the winding 22 in the appropriate direction, the winding tendsto move axially, towards the right (as viewed in FIG. 1), exerting onthe slide 3 a force F which is proportional to the mean strength ofcurrent 1,, passing through the winding. The pressure in the device 15is ultimately proportional to this mean current strength I,,,.

In the embodiment shown in FIG. 3, the magnet 18 is replaced by a ringmagnet 18, fitted around an H- .sectioned member 34, in which the limbsof the member 34 are of unequal length, an annular air gap 21 beingdefined between the shorter limb of the member 34 and a ring 35.

In the embodiment shown in FIG. 4, the magnet 18 is replaced by a coil36. In this case, a current which varies with the signal can be passedthrough the coil 36 and/or the winding 22.

In the embodiment of FIG. 5, the winding 22 is fixed on a drum 26slidable to an axial hub 27, fixed to the pole piece 19. The drum 26 isconnected by two or more levers 28, pivotally mounted at 29 on the body1, to a cup 30, biased against the slide 3 by a spring 24. The pivot 29is nearer to the pivotal connection between the levers 28 and the cup 20than to the pivotal connection between the levers 28 and the drum 26. Inuse, current is passed through the winding 22 whereby the winding andthe drum 26 move to the left as viewed in FIG. this movement istransmitted via the levers 28 to the cup 30 (and hence to the slide 3)with amplitude reduced, that is to say with the force increased, i.e.with a mechanical advantage.

The embodiment of FIG. 6 is generally similar to that shown in FIG. 1except that the cup 23 is hooked over the slide 3. Additionally, athrust pin 31 extends axially through the pole piece 19, the cup and themagnet 18, which is ring-shaped for this purpose, and bears against theslide 3. In the absence of current, the pressure P in the device 15 isproportional to a force (I) exerted on the pin 31; when current of meanstrength l,, is passed through the winding 22 in a sense to move thewinding 22 to the left as viewed in FIG. 6, it exerts on the slide 3 aforce F proportional to 1,, and opposite in direction to the forcef. Thepressure P,, falls and becomes proportional to f F, that is to say thatthe value by which it falls is proportional to l,,,.

In the embodiment shown in FIG. 7, the bore 2 is connected to a chamber16 by an aperture through which a thrust pin 32 extends. Equilibrium isestablished when the value of the force F is equal to s.P,,, s being thecross-sectional area of the pin 33. The force F is thus smaller than thevalue it will have in the embodiment in FIG. 1.

In the embodiment shown in FIG. 1, the spring 24 can be pre-stressed asto bring the slide 3 into a position in which the passages 9 and 14 arein communication even at maximum pressure. Then, the winding 22 beingarranged to be energized so as to be subjected to a force directedtowards the left as viewed in FIG. 1, the pressure in the device 15would have a value P in the absence of current in the winding 22, but,with current flowing through that winding, would fall by an amountrelated linearly to the mean strength of that current.

What is claimed is:

1. In an electrically operated valve for delivering a fluid pressuregoverned by a control signal,

a. feed pipe means,

b. means defining an outlet,

c. a fluid pressure source,

d. a distributor connected to said fluid pressure source and said feedpipe and outlet means,

e. said distributor having slide means selectively placing the feed pipemeans in communication with said source of fluid under pressure and withthe outlet,

f. a fluid actuated device associated with said distributor,

g. means subjecting the slide means to a first axial force dependent onpressure within said associated fluid-actuated device, and

h. an electrodynamic motor, having a winding through which flows acurrent governed by the control signal, the said winding constitutingthe moving part of the electrodynamic motor and being connected to theslide means to apply a second axial force thereto.

2. A valve as claimed in claim 1, in which the electrodynamic motorincludes a permanent magnet.

3. A valve as claimed in claim 1, in which the electrodynamic motorcomprises one fixed winding for creating a magnetic field, and

one moving winding.

4. A valve as claimed in claim 1, in which the force acting on thewinding and the force dependent on the pressure in said associateddevice act in opposite directions so as to cancel each other out atleast partially.

5. A valve as claimed in claim 4, further comprising linking meansconnecting the winding to the slide means, said linking means applying amechanical advantage to the slide means.

6. A valve as claimed in claim 1, in which the force acting on thewinding and the force dependent on the pressure in said associateddevice act in the same direction, said valve further comprising meansexerting a force on the slide means opposite in direction to the otherforces.

7. A valve as claimed in claim 6, in which the means exerting theopposite force comprises a spring.

8. A valve as claimed in claim 7, in which the spring is pre-stressedand exerts sufficient force on the slide means to retain the slide meansin a position in which the feed pipe means is in communication with thesource of fluid under pressure, even when the pressure in the associateddevice is at a maximum, the said force being insufficient to hold theslide means in the said position once the force acting on the windinghas reached a predetermined value.

9. A valve as claimed in claim 1, in which the said means subjecting theslide means to a force dependent on the pressure in the associateddevice comprises means defining a chamber in communication with the feedpipe means, and

a movable thrust member, the thrust member being smaller in section thatthe slide means, one end portion of the thrust member being received insaid chamber, and the other end of the thrust member being movable withthe slide means.

10. A valve as claimed in claim 9, in which the said other end of thethrust member bears against the slide means.

1. In an electrically operated valve for delivering a fluid pressuregoverned by a control signal, a. feed pipe means, b. means defining anoutlet, c. a fluid pressure source, d. a distributor connected to saidfluid pressure source and said feed pipe and outlet means, e. saiddistributor having slide means selectively placing the feed pipe meansin communication with said source of fluid under pressure and with theoutlet, f. a fluid actuated device associated with said distributor, g.means subjecting the slide means to a first axial force dependent onpressure within said associated fluid-actuated device, and h. anelectrodynamic motor, having a winding through which flows a currentgoverned by the control signal, the said winding constituting the movingpart of the electrodynamic motor and being connected to the slide meansto apply a second axial force thereto.
 2. A valve as claimed in claim 1,in which the electrodynamic motor includes a permanent magnet.
 3. Avalve as claimed in claim 1, in which the electrodynamic motor comprisesone fixed winding for creating a magnetic field, and one moving winding.4. A valve as claimed in claim 1, in which the force acting on thewinding and the force dependent on the pressure in said associateddevice act in opposite directions so as to cancel each other out atleast partially.
 5. A valve as claimed in claim 4, further comprisinglinking means connecting the winding to the slide means, said linkingmeans applying a mechanical advantage to the slide means.
 6. A valve asclaimed in claim 1, in which the force acting on the winding and theforce dependent on the pressure in said associated device act in thesame direction, said valve further comprising means exerting a force onthe slide means opposite in direction to the other forces.
 7. A valve asclaimed in claim 6, in which the means exerting the opposite forcecomprises a spring.
 8. A valve as claimed in claim 7, in which thespring is pre-stressed and exerts sufficient force on the slide means toretain the slide means in a position in which the feed pipe means is incommunication with the source of fluid under pressure, even when thepressure in the associated device is at a maximum, the said force beinginsufficient to hold the slide means in the said position once the forceacting on the winding has reached a predetermined value.
 9. A valve asclaimed in claim 1, in which the said means subjecting the slide meansto a force dependent on the pressure in the associated device comprisesmeans defining a chamber in communication with the feed pipe means, anda movable thrust member, the thrust member being smaller in section thatthe slide means, one end portion of the thrust member being received insaid chamber, and the other end of the thrust member being movable withthe slide means.
 10. A valve as claimed in claim 9, in which the saidother end of the thrust member bears against the slide means.